githooks(5) Manual Page

NAME

githooks - Hooks used by git

SYNOPSIS

$GIT_DIR/hooks/*

DESCRIPTION

Hooks are little scripts you can place in $GIT_DIR/hooks
directory to trigger action at certain points. When
git-init is run, a handful of example hooks are copied into the
hooks directory of the new repository, but by default they are
all disabled. To enable a hook, rename it by removing its .sample
suffix.

Note

It is also a requirement for a given hook to be executable.
However - in a freshly initialized repository - the .sample files are
executable by default.

This document describes the currently defined hooks.

applypatch-msg

This hook is invoked by git-am script. It takes a single
parameter, the name of the file that holds the proposed commit
log message. Exiting with non-zero status causes
git-am to abort before applying the patch.

The hook is allowed to edit the message file in place, and can
be used to normalize the message into some project standard
format (if the project has one). It can also be used to refuse
the commit after inspecting the message file.

The default applypatch-msg hook, when enabled, runs the
commit-msg hook, if the latter is enabled.

pre-applypatch

This hook is invoked by git-am. It takes no parameter, and is
invoked after the patch is applied, but before a commit is made.

If it exits with non-zero status, then the working tree will not be
committed after applying the patch.

It can be used to inspect the current working tree and refuse to
make a commit if it does not pass certain test.

The default pre-applypatch hook, when enabled, runs the
pre-commit hook, if the latter is enabled.

post-applypatch

This hook is invoked by git-am. It takes no parameter,
and is invoked after the patch is applied and a commit is made.

This hook is meant primarily for notification, and cannot affect
the outcome of git-am.

pre-commit

This hook is invoked by git-commit, and can be bypassed
with --no-verify option. It takes no parameter, and is
invoked before obtaining the proposed commit log message and
making a commit. Exiting with non-zero status from this script
causes the git-commit to abort.

The default pre-commit hook, when enabled, catches introduction
of lines with trailing whitespaces and aborts the commit when
such a line is found.

All the git-commit hooks are invoked with the environment
variable GIT_EDITOR=: if the command will not bring up an editor
to modify the commit message.

prepare-commit-msg

This hook is invoked by git-commit right after preparing the
default log message, and before the editor is started.

It takes one to three parameters. The first is the name of the file
that contains the commit log message. The second is the source of the commit
message, and can be: message (if a -m or -F option was
given); template (if a -t option was given or the
configuration option commit.template is set); merge (if the
commit is a merge or a .git/MERGE_MSG file exists); squash
(if a .git/SQUASH_MSG file exists); or commit, followed by
a commit SHA1 (if a -c, -C or --amend option was given).

If the exit status is non-zero, git-commit will abort.

The purpose of the hook is to edit the message file in place, and
it is not suppressed by the --no-verify option. A non-zero exit
means a failure of the hook and aborts the commit. It should not
be used as replacement for pre-commit hook.

The sample prepare-commit-msg hook that comes with git comments
out the Conflicts: part of a merge's commit message.

commit-msg

This hook is invoked by git-commit, and can be bypassed
with --no-verify option. It takes a single parameter, the
name of the file that holds the proposed commit log message.
Exiting with non-zero status causes the git-commit to
abort.

The hook is allowed to edit the message file in place, and can
be used to normalize the message into some project standard
format (if the project has one). It can also be used to refuse
the commit after inspecting the message file.

The default commit-msg hook, when enabled, detects duplicate
"Signed-off-by" lines, and aborts the commit if one is found.

post-commit

This hook is invoked by git-commit. It takes no
parameter, and is invoked after a commit is made.

This hook is meant primarily for notification, and cannot affect
the outcome of git-commit.

pre-rebase

This hook is called by git-rebase and can be used to prevent a branch
from getting rebased.

post-checkout

This hook is invoked when a 'git-checkout' is run after having updated the
worktree. The hook is given three parameters: the ref of the previous HEAD,
the ref of the new HEAD (which may or may not have changed), and a flag
indicating whether the checkout was a branch checkout (changing branches,
flag=1) or a file checkout (retrieving a file from the index, flag=0).
This hook cannot affect the outcome of 'git-checkout'.
This hook can be used to perform repository validity checks, auto-display
differences from the previous HEAD if different, or set working dir metadata
properties.
post-merge

This hook is invoked by git-merge, which happens when a git-pull
is done on a local repository. The hook takes a single parameter, a status
flag specifying whether or not the merge being done was a squash merge.
This hook cannot affect the outcome of git-merge and is not executed,
if the merge failed due to conflicts.

This hook can be used in conjunction with a corresponding pre-commit hook to
save and restore any form of metadata associated with the working tree
(eg: permissions/ownership, ACLS, etc). See contrib/hooks/setgitperms.perl
for an example of how to do this.

pre-receive

This hook is invoked by git-receive-pack on the remote repository,
which happens when a git-push is done on a local repository.
Just before starting to update refs on the remote repository, the
pre-receive hook is invoked. Its exit status determines the success
or failure of the update.

This hook executes once for the receive operation. It takes no
arguments, but for each ref to be updated it receives on standard
input a line of the format:

<old-value> SP <new-value> SP <ref-name> LF

where <old-value> is the old object name stored in the ref,
<new-value> is the new object name to be stored in the ref and
<ref-name> is the full name of the ref.
When creating a new ref, <old-value> is 40 0.

If the hook exits with non-zero status, none of the refs will be
updated. If the hook exits with zero, updating of individual refs can
still be prevented by the update hook.

Both standard output and standard error output are forwarded to
git-send-pack on the other end, so you can simply echo messages
for the user.

update

This hook is invoked by git-receive-pack on the remote repository,
which happens when a git-push is done on a local repository.
Just before updating the ref on the remote repository, the update hook
is invoked. Its exit status determines the success or failure of
the ref update.

The hook executes once for each ref to be updated, and takes
three parameters:

the name of the ref being updated,

the old object name stored in the ref,

and the new objectname to be stored in the ref.

A zero exit from the update hook allows the ref to be updated.
Exiting with a non-zero status prevents git-receive-pack
from updating that ref.

This hook can be used to prevent forced update on certain refs by
making sure that the object name is a commit object that is a
descendant of the commit object named by the old object name.
That is, to enforce a "fast forward only" policy.

It could also be used to log the old..new status. However, it
does not know the entire set of branches, so it would end up
firing one e-mail per ref when used naively, though. The
post-receive hook is more suited to that.

Another use suggested on the mailing list is to use this hook to
implement access control which is finer grained than the one
based on filesystem group.

Both standard output and standard error output are forwarded to
git-send-pack on the other end, so you can simply echo messages
for the user.

post-receive

This hook is invoked by git-receive-pack on the remote repository,
which happens when a git-push is done on a local repository.
It executes on the remote repository once after all the refs have
been updated.

This hook executes once for the receive operation. It takes no
arguments, but gets the same information as the
pre-receive
hook does on its standard input.

This hook does not affect the outcome of git-receive-pack, as it
is called after the real work is done.

This supersedes the post-update hook in that it gets
both old and new values of all the refs in addition to their
names.

Both standard output and standard error output are forwarded to
git-send-pack on the other end, so you can simply echo messages
for the user.

The default post-receive hook is empty, but there is
a sample script post-receive-email provided in the contrib/hooks
directory in git distribution, which implements sending commit
emails.

post-update

This hook is invoked by git-receive-pack on the remote repository,
which happens when a git-push is done on a local repository.
It executes on the remote repository once after all the refs have
been updated.

It takes a variable number of parameters, each of which is the
name of ref that was actually updated.

This hook is meant primarily for notification, and cannot affect
the outcome of git-receive-pack.

The post-update hook can tell what are the heads that were pushed,
but it does not know what their original and updated values are,
so it is a poor place to do log old..new. The
post-receive hook does get both original and
updated values of the refs. You might consider it instead if you need
them.

When enabled, the default post-update hook runs
git-update-server-info to keep the information used by dumb
transports (e.g., HTTP) up-to-date. If you are publishing
a git repository that is accessible via HTTP, you should
probably enable this hook.

Both standard output and standard error output are forwarded to
git-send-pack on the other end, so you can simply echo messages
for the user.

pre-auto-gc

This hook is invoked by git-gc --auto. It takes no parameter, and
exiting with non-zero status from this script causes the git-gc --auto
to abort.